Message Center Displays: DTE

The DTE is calculated in the PCM using the Running Average Fuel Economy (RAFE), which is the fuel economy up to 400 km (250 miles), and the fuel level input from the fuel sender to determine how many kilometers (miles) the vehicle can be driven based on the remaining fuel in the tank. The DTE displayed value can increase, or decrease, or stay the same value depending on customer driving patterns.

The Running Average Fuel Economy (RAFE) is not transmitted over the CAN, however the IPC will show an invalid Running Average Fuel Economy (RAFE) value in Engineering Test Mode. The DTE can vary in the short term by up to 80 km (50 miles), but is usually within 16 km (10 miles). Even if the fuel economy is relatively constant, the DTE can be off over a 80 km (50 mile) range by -24% to +38%.

The DTE display and the fuel gauge both use the fuel level input from the fuel tank and engine fuel consumption to provide their respective functions. If the fuel gauge doesn't function correctly, both the fuel gauge and the DTE display are affected.

If the DTE does not function correctly and the fuel gauge is correct, then Running Average Fuel Economy (RAFE), odometer or vehicle speed related input can be invalid.

The PCM defaults to a preset baseline L/100km (mpg) when the keep alive memory is reset or PCM is flashed and changes afterward based on driving habits and conditions.

NOTE: The customer calculated DTE can be higher or lower than the DTE displayed in the message center due to changes in driving conditions. It is important to understand how the DTE is calculated and the factors that impact the DTE display when determining how to address any DTE concerns.

Since the DTE is calculated and averaged over a longer period of time (400 km [250 miles]), varying driving conditions can have a significant impact on the current or short term DTE as opposed to the displayed DTE. This difference often leads to customer complaints of incorrect or invalid DTE. The following list provides some (not all) of the driving conditions that may lead to an incorrect or fluctuating DTE concern:

Changing between towing/not towing.
Changing driving between city and highway.
Allowing the vehicle to idle for long periods of time.
Using the remote start feature frequently to allow the vehicle to warm up, particularly when parked on a grade.
Parking or driving on grades.
Inconsistent use of gasoline or E85 fuels.
Over-fueling or not filling the tank completely (trickle filling at above full, partial filling with less than 10% of tank capacity).

The PCM uses the following network messages to control the DTE.

Fuel alcohol percent
Fuel flow volume display
Odometer count
Transport mode
Fuel level input from the IPC

The IPC receives all messages from the GWM over the HS-CAN3. The GWM receives the transport mode message from the BCM over the HS-CAN1 and the fuel alcohol percent, fuel flow volume display and the odometer count messages from the PCM over the HS-CAN1.